man krb5_checksumsize (Fonctions bibliothèques) - krb5_checksum ,

NAME

krb5_checksum ,krb5_checksum_disable ,krb5_checksum_is_collision_proof ,krb5_checksum_is_keyed ,krb5_checksumsize ,krb5_cksumtype_valid ,krb5_copy_checksum ,krb5_create_checksum ,krb5_crypto_get_checksum_typekrb5_free_checksum ,krb5_free_checksum_contents ,krb5_hmac ,krb5_verify_checksum - creates, handles and verifies checksums

LIBRARY

Kerberos 5 Library (libkrb5, -lkrb5)

SYNOPSIS

typedef Checksum krb5_checksum; krb5_context context krb5_cksumtype type krb5_context context krb5_cksumtype type krb5_context context krb5_cksumtype type krb5_context context krb5_cksumtype ctype krb5_context context krb5_cksumtype type size_t *size krb5_context context krb5_crypto crypto unsigned usage_or_type void *data size_t len Checksum *result krb5_context context krb5_crypto crypto krb5_key_usage usage void *data size_t len Checksum *cksum krb5_context context krb5_crypto crypto krb5_cksumtype *type krb5_context context krb5_checksum *cksum krb5_context context krb5_checksum *cksum krb5_context context krb5_cksumtype cktype const void *data size_t len unsigned usage krb5_keyblock *key Checksum *result krb5_context context const krb5_checksum *old krb5_checksum **new

DESCRIPTION

The krb5_checksum structure holds a Kerberos checksum. There is no component inside krb5_checksum that is directly referable.

The functions are used to create and verify checksums. krb5_create_checksum creates a checksum of the specified data, and puts it in result . If crypto is NULL , usage_or_type specifies the checksum type to use; it must not be keyed. Otherwise crypto is an encryption context created by krb5_crypto_init , and usage_or_type specifies a key-usage.

krb5_verify_checksum verifies the checksum against the provided data.

krb5_checksum_is_collision_proof returns true is the specified checksum is collision proof (that it's very unlikely that two strings has the same hash value, and that it's hard to find two strings that has the same hash). Examples of collision proof checksums are MD5, and SHA1, while CRC32 is not.

krb5_checksum_is_keyed returns true if the specified checksum type is keyed (that the hash value is a function of both the data, and a separate key). Examples of keyed hash algorithms are HMAC-SHA1-DES3, and RSA-MD5-DES. The hash functions MD5, and SHA1 are not keyed.

krb5_crypto_get_checksum_type returns the checksum type that will be used when creating a checksum for the given crypto context. This function is useful in combination with krb5_checksumsize when you want to know the size a checksum will use when you create it.

krb5_cksumtype_valid returns 0 or an error if the checksumtype is implemented and not currently disabled in this kerberos library.

krb5_checksumsize returns the size of the outdata of checksum function.

krb5_copy_checksum returns a copy of the checksum krb5_free_checksum should use used to free the new checksum.

krb5_free_checksum free the checksum and the content of the checksum.

krb5_free_checksum_contents frees the content of checksum in cksum .

krb5_hmac calculates the HMAC over data (with length len ) using the keyusage usage and keyblock key . Note that keyusage is not always used in checksums.

krb5_checksum_disable globally disables the checksum type.

SEE ALSO

krb5_crypto_init(3) ,krb5_encrypt()